View finder for photographic cameras



Mara. 7, 1939. H. BECKER 2,149,384

VIEW FINDER FOR PHOTOGRAPHIC CAMERAS Filed April 21, 1937 B a r Patented .Man 7, 1939 VIEW FINDER FOR PHOTOGRAPHIC AMERAS Helmut Becker, Wetzlar, Germany, assignor to AErnst Leitz, G. m. b. H., Wetzlar, Germany Application April 21, 1937, Serial No. 138,101

Germany April 25, 1936 1 Claim.

This invention relates to view finders with adjustable masks for framing the field of view for use on photographic cameras. Such finders maybe adjusted by means of an adjusting ring or like element having a scale indicating the focal length of the objective which happens to be used. Photographic cameras may be adapted for use with photographic objectives of various focal lengths and since the eld of view taken in by a lens depends upon its focal length, the field of view which appears upon the film or ground glass of the camera varies with the focal length of the selected camera objective. In order that the field of view which is framed within the view finder shall correspond to the eld of view which will be photographed on the film it is necessary to provide a finder in which the size of the field of view may be adjusted with eah lens change in the camera. It is also desirable to provide a nder which may be adjusted without interference with any other part of the camera. Cameras are sometimes so constructed that parts thereof on the upper portion of the housing interfere or obscure to some extent the operations of the view finder. The object of this invention is to provide a view iinder in which the mask is adjusted by operation of the ocular mounting whereby the same may be adjusted free from hindrance by other parts of the camera.

In the drawing accompanying this specification and illustrating the invention Fig. 1 is an end view of the finder looking at the ocular.

Fig. 2 is a side view with parts broken away and in section to expose the interior construction.

Fig. 3 i's an enlarged cross sectional view taken substantially on the line 3-3 of Fig. 2.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3 with` parts broken away.

The view finder consists of a tubular casing I which is adapted to be attached to or placed within a camera as a self-contained unitary device. Within the casing there is mounted a suitable optical inder system which includes the ocular 2, the objective 3 and interposed lenses and prisms 4 and 5. The iinder mask consists of two lamellae 6 and 'I adapted to be adjusted so as to form a view finder opening 8.

The lamellae slide in inclined guide Ways I0 in the supporting walls II. Each lamella carries a 5 pin I2 which engages a slot I3 in an adjusting ring I4 which is provided with a toothed segment I5. The latter meshes with a gear I 6 on a shaft I'l. Near the ocular the shaft carries another gear I8 which also engages a toothed segment I9. 10 The latter is attached to and rotates with the ocular ring mounting 20. The ocular mounting carries a focal scale 2I to be read with reference to a xed index pin 22 which appears through a slot 23.

By rotating the ocular mounting the lamellae 6 and 1 are adjusted through the described instrumentalities to accord with a focal length indicated on the scale 2l with reference to the index pin 22.

When the ring I4 is rotated, the slots I2 by 20 engagement with the lamellae pins I3 moves the lamellae in the guide ways I0 to increase or decrease the finder view opening 8.

I claim:

A photographic view finder comprising a cas- 25 ing, an optical View finder system Within the casing, movable mask members in said system for rectangularly framing the field of view, a toothed rotatable ring operatively connected to the mask members to mpve and adjust the same to frame the field of View, an ocular in said optical system, a rotatable mounting for said ocular, a pin in said view finder in fixed relation to the optical axis of the view finder, a scale on said mounting indicating the extent of its rotation with relation to said fixed pin whereby to adjust the said mask members to frame the field of View in accordance with the focal length of a camera objective with which said View nder is used, a toothed segment secured to the ocular mounting, a shaft and pinions on said shaft in mesh with the said segment and toothed ring for operating the latter when the said ocular mounting is rotated.

HELMUT BECKER. 

